Today, information processing apparatuses such as PCs and portable devices with mass storage capabilities including large-capacity hard disk or DVD drives have come into general use. A large number of content users place huge quantities of contents such as music data and image data into appropriate storing means for storage and management purposes. These kinds of data are compressed using the MP3, ATRAC or other suitable standard before being stored as digital data. The data may be encrypted as needed for management.
Recently popularized forms of content use typically involve having desired music contents downloaded from music distribution servers such as EMD (Electronic Music Distribution) servers onto recording media in each user's PC. The downloaded contents may be output (i.e., checked out) from the PC as needed to the user's portable device (PD) for content reproduction.
There exist so-called jukebox applications for managing and reproducing music contents as well as for controlling their transfer to external devices such as the portable device (PD). The representative jukebox applications include SonicStage (trademark), SonicStage Simple Burner (trademark), MGIQLIP (trademark), Windows Media Player (trademark), Real Player (trademark), and iTunes (trademark). Each application has the ability to download EMD contents and to transfer song data from the hard disk (HD) in the PC to the connected device or media.
Before any song data stored on the hard disk (HD) in the PC can be transferred to the portable device (PD) or other suitable equipment or media connected to the PC, it is necessary to select songs constituting the contents to be transferred.
In recent years, the hard disk drives used typically as the data storing means for the PC and other equipment have gained huge storage capacities. The similar trend toward greater recording capabilities has also been observed with the storing means for portable devices (PD). With such mass storage media in general use, it has become almost common practice today to transfer contents not on a song by song basis but as a large group of selected songs between devices or between equipment and media.
Where such multiple songs are to be transferred illustratively to the portable device (PD) connected as a destination for the transfer, it is preferable to check whether any of the songs have already been transferred so that the duplicate transfer of songs may be avoided. That check, however, can take up a considerable part of the transfer process especially when there is a large number of contents to be checked at the source or at the destination of the transfer.
For example, when any one of the above-mentioned applications is used to transfer contents, the GUI (Graphic User Interface) of the application usually offers the ability to display a list of transferable songs. However, it is generally up to the user to verify whether the numerous songs included in the displayed list have already been transferred, one song at a time.
Apple Computer's iTunes, one of the jukebox applications, has a function called “Auto Sync” that works with ipod, a portable device marketed by the same company. This function involves comparing song data in the content database of the PC (i.e., on the hard disk), which may be supplemented from time to time by new songs from downloaded EMD contents or ripped CDs, with the song data in the connected portable device (i.e., ipod). Following the comparison, any song data that is found on the hard disk of the PC but not in ipod is transferred from the PC to iPod so that the song data on both sides will be synchronized. Descriptions of ipod and the Auto Sync function are found at a non-patent documents 1 and 2.
Using that function makes it possible to transfer automatically the song data from the hard disk of the PC to ipod. However, the function can only work with devices such as iPod which have a storage capacity large enough to accommodate all songs held on the hard disk of the PC. When song data is to be transferred by this function, the quantity of the data to be transferred from the hard disk of the PC must not exceed the capacity of the media that will accommodate the transferred data.
If the amount of the data to be transferred from the hard disk of the PC exceeds the capacity of the destination media, then not all target data to be transferred can be accommodated by the media. In the end, the user is required to select manually the contents to be transferred.
[Non-Patent Document 1]
http://www.apple.co.jp/ipod/
[Non-Patent Document 2]
http://www.apple.co.jp/ipod/autosync.html